In-situ observation of ion beam-induced nanostructure formation on a Cu(In,Ga)Se2 Surface

We report a phenomenological study of Cu(In,Ga)Se2 (CIGS) dots and their morphological transition into nano-ridge shapes induced by application of a focused ion beam (IB) to CIGS film. Real-time observations of nano-structure evolution during IB irradiation were obtained by recording sequential images at various ion energies of 1 to 30 keV. We observed that as irradiation time increased, the dots became larger and developed elongated ridge structures under continuous sputtering. This transition process was induced by a combination of the Ostwald ripening processes and cluster diffusion. Compositional analysis revealed that the nano-dots changed from pristine CIGS to Cu-rich CIGS. The Ga content of the dots was also found to increase due to sputtered implantation, while levels of In and Se decreased. Copyright (C) 2012 John Wiley & Sons, Ltd.